Case of Dispute over Infringement of Patent Right for Invention by "Air Purification Device"

October 24, 2022

Case brief:

Darwin Technology International Limited (hereinafter referred to as Darwin Company) is the patentee of the invention with the patent name of "Air Purification Device". The patent is mainly used in air purification apparatus to prevent haze, and is patented on December 26, 2007. Darwin Company found that since November 2014, Beijing Science and Technology Branch of Aerospace Communications Holdings Co., Ltd. (hereinafter referred to as Aerospace Communications Beijing Branch) has produced, sold and promised to sell "J ·inG Wujing High Efficiency Vertical Air Purifier" (hereinafter referred to as the alleged infringing product) that infringed Darwin Company's patent right for invention involved. Nanjing Yujie Environmental System Technology Co., Ltd. (hereinafter referred to as Yujie Company) provided and sold the electrostatic settling filter screen specially used to implement the patent involved to Aerospace Communications Beijing Branch. In 2012, Darwin Company sent a lawyer's letter to Yujie Company for its unlicensed production of electrostatic settling filter screen to help infringement of the patent rights involved. Darwin Company filed a lawsuit to request the two defendants to stop infringement, compensate for losses and reasonable expenses totaling 1 million yuan.

The court of first instance held that the technical solution of the alleged infringing product fell within the protection scope of claims 1-3, 15, 18-21 and 24-27 of the patent involved, and the acts involved of Aerospace Communications Beijing Branch and Yujie Company constituted infringement, and the defense proposed that the alleged infringing product used the existing technology could not be established. Aerospace Communications Beijing Branch manufactured and sold the alleged infringing product involved that infringed Darwin Company's patent rights, and Yujie Company provided the honeycomb coagulation filter screen therein. Although the honeycomb coagulation filter screen in the alleged infringing product can be used for air conditioning, it has the size suitable for the air purifier product involved, and its particle deposition can only be realized when it is used in the product for implementing the patent involved. Therefore, the honeycomb coagulation filter screen belongs to the special product for implementing the patent involved and does not have "substantial non-infringing use". Yujie Company was aware of the existence of the patent involved and knew that the honeycomb coagulation filter screen was a special part for implementing the patent involved, but still provided it to Aerospace Communications Beijing Branch. Yujie Company serves as an infringer assistor and has a subjective intention. Therefore, Yujie Company has helped Aerospace Communications Beijing Branch in its infringement, which constitutes a joint infringement. The first instance decided that the two defendants should stop the infringement and jointly compensate Darwin Company for the economic loss of 350000 yuan and reasonable expenses of 150000 yuan. Yujie Company and Aerospace Communications Beijing Branch appealed against the judgment. The second instance rejected the appeal and upheld the original judgment.


This case is a typical case of identifying contributory infringement in patent infringement dispute. This case involves not only the analysis of the use of technology, but also the judgment of the assistor's subjective intention. This case is of reference significance for how to identify the "substantial non-infringing use" rule in the litigation.

(Source of case: Beijing Higher People's Court)